Calcium is the 20th element on the Periodic Table. It's Atomic Number is 40.078 It is in the second group of the table, the Alkaline Earth Metal Group. It was discovered by Sir Humphrey Davvy in 1806.
Calcium is a metal and it makes up 3% of the Earths crust. It is found in leaves, bones, teeth and shells. Most of this things are hard because Calcium is a hard metal.
Joella Thornton - MASC PAGECALCIUM - CA
Calcium is the 20th element on the Periodic Table. It's Atomic Number is 40.078 It is in the second group of the table, the Alkaline Earth Metal Group. It was discovered by Sir Humphrey Davvy in 1806.
Calcium is a metal and it makes up 3% of the Earths crust. It is found in leaves, bones, teeth and shells. Most of this things are hard because Calcium is a hard metal.
=[1]A,M Helmenstine, (2010), Calcium Facts, Retrieved 8 November 2010 from http://chemistry.about.com/od/elementfacts/a/calcium.htm
M, Winter, (2010) Calcium: the essentials, Retrieved 2 November 2010 from http://www.webelements.com/calcium/